diff --git a/notebooks/xeus-javascript.ipynb b/notebooks/xeus-javascript.ipynb
index 827de31..73ca25c 100644
--- a/notebooks/xeus-javascript.ipynb
+++ b/notebooks/xeus-javascript.ipynb
@@ -132,7 +132,7 @@
    },
    "outputs": [],
    "source": [
-    "# this works\n",
+    "// this works\n",
     "console.log(fubar)"
    ]
   },
@@ -146,7 +146,7 @@
    },
    "outputs": [],
    "source": [
-    "# this does not\n",
+    "// this does not\n",
     "console.log(fubar_local)"
    ]
   }